1. Field of the Invention
The present invention relates to a device for producing graphene, and more particularly to the device for a continuous production of graphene flakes by an electrochemical method.
2. Description of Related Art
In 2004, the research team of Professor A. K. Geim at the University of Manchester, England attached a thin layer of graphite (known as graphene) on an adhesive tape and another adhesive tape on the other side of the graphene, and then torn the two adhesive tapes apart to exfoliate the graphene into two thinner layers, and the aforementioned procedure is repeated for several times to obtain single atomic layer of graphene. Through the observation by a transmission electron microscope (TEM), carbon atoms in graphene has a highly-ordered arrangement.
The graphene has many excellent properties including the high mechanical strength (˜1,100 GPa), hardness, brittleness and flexibility, and gases cannot penetrate through the thin layer of graphene, and a high heat conductivity coefficient up to 5300 W/m·K which is better than carbon nanotubes and diamond, and the electron mobility of graphene at room temperature exceeds 15000 cm2/V·s which is higher than the carbon nanotubes (approximately equal to 10000 cm2/V·s) and more than ten times of crystalline silicon (1400 cm2/V·s), and the resistance of graphene is approximately equal to 10−6 Ω·cm which is lower than that of copper or silver.
In general, graphene is prepared or produced by the following four main methods. (1) Mechanical exfoliation method: Graphene is manufactured from graphite, and this method can produce single-layer or multi-layer graphene simply, easily and quickly, but this method is suitable for the manufacture of a small quantity of graphene only; (2) Chemical vapor deposition method or an epitaxial growth method: Graphene is manufacturing by passing and depositing a thermally cracked hydrocarbon gas source onto a nickel or copper plate. This method has the feature of producing large-area single-layer or multi-layer graphene easily and the difficulty of controlling the uniformity and thickness of the graphene; (3) Method of growing graphene on an insulating substrate: A very thin layer of graphene is grown on a surface of silicon carbide. The method has the drawbacks of incurring a high cost and having difficulties of manufacturing large-area graphene; and (4) Method of using organic acidic solvent to insert layers to produce graphene oxide (GO) and obtaining grapheme by a reduction procedure: This method has the drawbacks of requiring a long processing time, and having an inconsistent quality of the grapheme since the reduced grapheme may be deformed or warped easily.
In addition, an electrochemical method can be used. Graphene flakes are produced by changing an electric voltage at room temperature. This method can simplify the manufacturing process without requiring any high-temperature reduction procedure and can produce large graphene flakes easily.
As described above, the method of producing grapheme by an electrochemical method has the advantages or using a simple, easy and quick manufacturing procedure and producing high-quality large-area grapheme. At present, related industries require a method and a device of producing graphene flakes by a continuous automated electrochemical method to exfoliate graphite electrodes, so as to reduce the labor and manufacturing time and produce graphene flakes by mass production. Therefore, the present invention provides a device for a continuous production of graphene flakes by an electrochemical method that takes both cost and manufacturing time into consideration and no longer requires a high temperature reduction procedure, and thus the present invention can achieve a quick mass production of high-quality graphene flakes.